Pivot centres



J. HADFIELD PIVOT CENTRES July 11, 1961 Original Filed May 21, 1956 FIG.

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United States Patent() 2,992,050 PIVOT CENTRES James Hadfield, ZRomiley, Chester, England, assignor of one-half to Beyer Peacock & Company Limited, Manchester, England, a British company Original application May 21, 1956, Ser. No. 586,150,

now Patent No. 2,929,662, dated Mar. 22, 1960. Divided and this application May 18, 1959, Ser. No. 814,076 7 Claims priority, application Great Britain May 24, 1955 '3 Claims. (Cl. 308137) This application is a division of application Serial No. 586,150, filed May 21, 1956, now Patent No. 2,929,662, issued March 22, 1960.

This invention relates to pivot centres for articulated and bogie locomotives of all types and in particular diesel-electric, diesel-hydraulic, diesel-mechanical, gas turbine and electric locomotives.

The object of the invention is the provision of an improved pivot centre of the above character, which, amongst other advantages, can be applied, for example, to bogie pivot centres on electric or diesel locomotives without restricting the basic design of the bogies or imposing limitations on the space available for traction motors or gear boxes, or for access to such transmission units for inspection and maintenance.

The invention consists broadly of a pivot centre for articulated and bogie locomotives comprising a male member and a female member, said female member including a wearing element which is mounted so as to be movable towards the male member for taking up wear, wherein said wearing element is biased in the direction for taking up wear by means of a horizontally movable wedge which engages a surface of said wearing element and is itself biased by means of a long horizontal helical spring, said spring and said wedge being located on opposite sides of the pivot centre and said spring operating said wedge through the medium of a lever. In order-that the invention maybe the more clearly understood a pivot centre construction in accordance therewith will now be described, reference being made to the accompanying drawings wherein:

FIGURE 1 is a sectional elevation of said construction, the section being on line II of FIGURE 2.

FIGURE 2 is a sectional plan of the same, the section being on line II-II of FIGURE 1.

FIGURE 3 is a cross section of the same, the section being on line III-III of FIGURE 2.

Referring to the drawings, the construction comprises a female pivot member 1, 2 which is mounted on the frame structure 3 of the bogie or truck or alternatively the swing bolster of the bogie or truck if such is provided, and a male pivot member 4 attached to the superstructure of the locomotive which extends downwards engaging the female member. The male member 4 has a flat bottom bearing plate 5 which rests on a corresponding flat bearing plate 6 at the bottom of the female member and supports the weight of the superstructure.

The male member 4 is also fitted with a renewable ring 7 in the form of a truncated cone, and the female member 1, 2 is machined to the same contour, this arrangement being designed to permit a certain amount of tilting between the male and female members in both longitudinal and transverse directions.

The female member 1, 2 comprises a fixed bearing block 1 and an adjustable bearing block or wearing element 2 machined as mentioned above to the same conical contour as the ring 7 of the male member, with a clearance 8 between blocks 1 and 2 at each side to permit horizontal longitudinal movement of block 2 towards the male member as wear takes place.

The adjustable bearing block 2 is permanently biased towards the fixed block 1 by means of a spring loaded wedge 9 and wear on the circumferential bearing surfaces of the male and female members is thus automatically taken up.

The wedge 9 moves in a horizontal direction. It has its geometrical axis at right angles to the vdirection of movement of the adjustable bearing block 2 and its two faces are equally inclined in opposite directions with respect to said geometrical axis. One of said faces is in contact with the bearing block 2 and the other in contact with a fixed bearing block 10. The taper of the wedge 9 is so arranged that reversal of action can take place in response to the bearing blocks 1 and 2 being forced apart by the male member when the superstructure is being lowered into position on the bogies or trucks and also under conditions of tilting between the male and female members in a longitudinal direction.

The female member 1, 2 and the wedge 9 are housed in an oil-tight container which provides an oil bath. This container comprises a casting 14 having a recess 35 which contains the female member 1, 2 and the wedge 9. A cover plate 15 covers said recess 35 and the male member projects into said recess through a hole in said cover plate, with a dust seal 16 between said male member and the edge of said hole.

The wedge 9 is loaded by means of a long horizontal helical spring 19 actuating the wedge 9 by means of a lever 20 and compression link 21. The spring 19 is enclosed within a plunger 22 which slides in a bored hole 34 formed in the casting 14 on the side of the pivot centre remote from the wedge, and parallel to a horizontal line at right angles to the direction of travel of the adjustable bearing block 2, i.e. parallel to that diameter of the pivot centre which contains the clearances 8. The lever 20 oscillates in a second recess 23 formed in the said casting 14, abouta fixed vertical pivot pin 24 between its ends. The hole 34 breaks into the recess 23 and the spring 19 is in compression between a screwed plug -.25, screwed into the outer end of said hole 34, and one: end of the lever: 20. The compression link 21 extends from the other endofsaid lever .to'the Wedge 9 through an opening 36 in the partition between the recesses 23 and 35. The pivot pin 24 is disposed so that said lever affords a mechanical advantage. This mechanical advantage and the space available to accommodate the spring 19 permits the employment of a spring of relatively slight section and optimum deflection rate. All the working parts are enclosed in an oil bath constituted by the cavities 23 and 35 and the hole 34. The screwed plug 25 provides for removal of spring 19 and plunger 22 whilst the oiltight cover 26 provides for removal of the lever 20 after the cover plate 15 and pin 24 have been removed, The cover plate 15 covers both the cavity 23 and the recess 35.

The load applied to the wedge is such that under all conditions of Wear of the male and female pivot members there is no clearance betwen said pivot members in a longitudinal direction, thus eliminating all knocking which occurs when clearance exists in pivot centres and the consequential shock loads and damage to the structure of the locomotive which can occur under these conditions. Also the pressure exerted by the bearing blocks 1 and 2 on the male member creates a frictional resistance to rotation of the male member relative to the female member which greatly assists in preventing hunting or oscillation of the bogie or truck in the track.

The fact that the slidable bearing block 2 can be forced to move away from the fixed bearing block 1 is of the greatest importance. For example, if excessive tilting movement should take place as might happen in the case of a derailment the sliding block 2 withdraws as required and prevents binding between the male and female members which would otherwise occur, and relieves [the supa 3 porting structure from excessive strains which would be caused by such binding.

The conical form of the pivot members is also of great importance since it permits a vcertain amount of tilting in bothlongitudinal and'lateral directions without binding and also tends to minimize the stress created by snatching when starting heavy trains. This conical form in conjunction with the fact that the slidable block 2 can be. forcedback due to the reversible action of the wedge 9 is also of value in facilitating erection sincethe weight of the superstructure as it is lowered into position automatically forces the bearing blocks 1 andZ apart during entry of the. male member. Thus the assembly does not require any slackening of the spring or any manipulation of component parts.

The invention is particularly valuable for application to bogies or trucks wherein design features and space restrictions require a pivot centre, entirely contained within a small space in the vertical direction.

It will be seen that the loadingspring is parallel to the geometrical. axis of the wedge, but the arrangement is such that the extent of said spring beyond either end of said wedge is much less than the length of said spring, and thus a compact design is achieved.

I claim:

1. A pivot centre for articulated locomotives and bogie locomotives, comprising a female pivot member, a male pivot member extending downwardly into said female pivot member, said female pivot member including a wearing element mounted-so as to be movable towards the male. pivot member for taking up wear, a horizontally movable wedge engaging a surface of .saidwearing element, a horizontal helical spring located on the side of-the pivot centre opposite to that of said wedge and a lever coupling said spring to said wedge, whereby said spring biases said wedge in the direction for moving said wearing element for taking up wear, said female pivot member, wedge, spring and lever being housed in an oil tight container which provides an oil bath, and into which said male member projects through an oil-tight seal.

2. A pivot centre for articulated locomotives and bogie locomotives, comprising a casting having a recess adapted to form an oil bath, a female pivot member mounted in said recess, a male pivot member extending downwardly into said female pivotmember, said female pivot member including a wearing element mounted so as to be movable towards said male pivot member for taking up wear, a. horizontally movable wedge mounted in said recess and engaging a surface of said wearing element, a horizontal bore hole in said casting on the side of the pivot centre opposite to that of said wedge, a horizontal helical spring located in said bore hole, said casting having a second recess adapted to form an oil bath, a horizontal lever mounted in said second recess, said lever being pivoted between its ends about a fixed vertical axis, said bore hole breaking into said second recess and said spring being in compression between a fixed surface and one end of said lever, a compression link extending through an opening between said first and second recesses and acting as a strut between the other end of said lever and said wedge, whereby said spring biases said wedge in the direction for moving said wearing element for taking up wear, and a cover for said recesses through which the male member projects in sealed relation.

3. A pivot centre for articulated locomotives and bogie locomotives, comprising a frame, a female pivot member connected to said frame, a male pivot member extending downwardly into said female pivot member, said female pivot member including a wearing element movable towards the male pivot member for taking up wear, a horizontally movable wedge engaging a surface of said wearingelement, a horizontally-arranged helical spring on the opposite side of said male member from said wedge, a horizontal lever pivotally connected intermediate its ends to said frame, said spring being under compressionand in contact at one end with one end of said lever and at the other end with a fixed member on said frame, and a compression link between the other end of said lever and said wedge, said spring biasing said lever and said wedge in the direction for moving said wearing element toward said male member.

References Cited in the file of this patent UNITED STATES PATENTS 611,704 Morris Oct. 4, 1898 1,139,216 Ohr' May 11, 1915 2.3671613 Rich et al. Jan; 16, 1945 

